Blacknad wrote:

"A friend of mine has the idea of writing a sci-fi story about explorers landing on a planet only to find that everyone had committed suicide simultaneously."

I'm sure you are familiar with the TV series "Red Dwarf". For anyone not so try to find a DVD. I'm sure you would enjoy it. Anyway one of their programs was about a planet where everyone committed suicide, some virus had invaded. Our heroes had to fight off the virus and escape. Maybe "Red Dwarf" should be another thread?